Drawing-board and t-square



(No Model.)

0. H.- PRESCOTT.

DRAWING BOARD AND T SQUARE.

Patented Nov. 11, 1884.

WITNESSES J' 6. MM 22? M ez a jfor" .dttornez N. PETERS. PhMn-Lllhognphlr. Washvvglnll, 11c.

UNITED STATES PATENT OFFICE.

CLIFFORD H. PRESCOTT, OF LAWRENCE, MASSACHUSETTS.

DRAWING-BOARD AND T-SQUARE.

SPECIFICATION forming part of Letters Patent No. 308,040, dated Ncivember 11, 1884.

Application filed July 525, 1884. (No model.)

clare that the following is a full, clear, and

exact description of the same, reference being had to the annexed drawings, making a part of this specification, and to the letters and figures of reference marked thereon.

Figure l of the drawings is a perspective view of my invention, and Fig. 2 a cross-section taken through the board and T square.

The present invention has for its object to provide a combined drawing-board and T- square whereby the head of the square is at all times held true and snugly against the edge of the board, thus enabling better work to be done without the necessity of exercising the care heretofore required to keep the head of the T-square in a true line against the edge of the board. This object I attain by the construction substantially as shown in the drawings and hereinafter described and claimed.

in the accompanying drawings, A represents the drawing-board, and B the T-sqnare. The drawing-board A is provided on one or more of its edges with a groove, c, preferably a dovetail groove, so as to better retain the head of the T-square against the edge of the board, and preventing it from being disconnected, except by passing or sliding the head along until it passes beyond the end of the groove, a tongue, 1), upon the inner edge of the head of the T-square engaging with the groove a, said tongue and groove being of corresponding form.

Instead of making the tongue and groove direct from the material composing the drawing-board and head of the T-square, I prefer to construct the tongue and groove of brass or other suitable metal, and secure them in place by screws or other well-known means, thus rendering the tongue and groove more perfect, and fitting each other with greater accuracy than when made of wood, besides obtaining a much smoother surface between the tongue and groove, and thus enabling the head to more easily slide along the edge of the board.

Although I have shown the tongue and groove of dovetail form, and constructed scparately of metal, and afterward secured in place along the edge of the head and board, I do not desire to limit myself thereto, as any form of tongue and groove may be substituted and constructed directly from the material from which the T-square and board are made.

If preferred,the groove may be made on the head of the T-square and the tongue on the edge of the drawing-board.

Having now fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

l. A drawing-board having agroove on one or more of its edges,in combination with a T- square having its head provided with a tongue, substantially as and for the purpose specified.

, 2. A drawing board and T- square connected together by a dovetail and groove, substantially as and for the purpose described.

In testimony that I claim the above I have hereunto subscribed my name in the presence of two witnesses.

CLIFFORD H. rsnsoorr.

,W'itnesses:

CHARLES U. BELL, CLARA F. PREsooTT. 

